2,733 research outputs found
Automated Slope Stability Analysis of Zoned Dams
The study pertains to the pseudo-static stability analysis of zoned dams with geologic discontinuities in the foundation. Sequential unconstrained minimization technique in conjunction with Janbu\u27s generalized procedure of slices has been used for finding the critical slip surface and the corresponding minimum factor of safety. The method has been found to be quite efficient in solving such problems
Study of fragmentation using clusterization algorithm with realistic binding energies
We here study fragmentation using \emph{simulated annealing clusterization
algorithm} (SACA) with binding energy at a microscopic level. In an earlier
version, a constant binding energy (4 MeV/nucleon) was used. We improve this
binding energy criterion by calculating the binding energy of different
clusters using modified Bethe-Weizs\"{a}cker mass (BWM) formula. We also
compare our calculations with experimental data of ALADiN group. Nearly no
effect is visible of this modification
On the Torsion of Elastic Half Space with Penny Shaped Crack
The investigation deals with the effect of an embedded flaw-a penny-shaped crack in an elastic half-space subject to torsional deformation. The problem is reduced to a system of Fredholm integral equations. Graphical display of the results are included
Evaluation of catalyst for the oxidative ammonolysis of m-xylene.
Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.Sc.)--University of Windsor (Canada), 1972
From fusion to total disassembly: global stopping in heavy-ion collisions
Using the quantum molecular dynamics model, we aim to investigate the emis-
sion of light complex particles, and degree of stopping reached in heavy-ion
colli- sions. We took incident energies between 50 and 1000 MeV/nucleon. In
addition, central and peripheral collisions and different masses are also
considered. We ob- serve that the light complex particles act in almost similar
manner as anisotropic ratio. In other words, multiplicity of light complex
particles is an indicator of global stopping in heavy-ion collisions. We see
that maximum light complex particles and stopping is obtained for heavier
masses in central collisions
Limits on stable iron in TypeIa supernovae from NIR spectroscopy
We obtained optical and near-infrared spectra of TypeIa supernovae
(SNeIa) at epochs ranging from 224 to 496 days after the explosion. The
spectra show emission lines from forbidden transitions of singly ionised iron
and cobalt atoms. We used non-local thermodynamic equilibrium (NLTE) modelling
of the first and second ionisation stages of iron, nickel, and cobalt to fit
the spectra using a sampling algorithm allowing us to probe a broad parameter
space. We derive velocity shifts, line widths, and abundance ratios for iron
and cobalt. The measured line widths and velocity shifts of the singly ionised
ions suggest a shared emitting region. Our data are fully compatible with
radioactive Ni decay as the origin for cobalt and iron. We compare the
measured abundance ratios of iron and cobalt to theoretical predictions of
various SNIa explosion models. These models include, in addition to
Ni, different amounts of Ni and stable Fe. We can
exclude models that produced only Fe or only Ni in addition to
Ni. If we consider a model that has Ni, Ni, and
Fe then our data imply that these ratios are Fe / Ni
and Ni / Ni .Comment: 10 pages, 7 figures, Accepted for publication in A&
Beta amyloid oligomers and fibrils stimulate differential activation of primary microglia
<p>Abstract</p> <p>Background</p> <p>Beta amyloid (Aβ) peptides are the major constituents of the senile plaques present in Alzheimer's diseased brain. Pathogenesis has been associated with the aggregated form of the peptide as these fibrils are the conformation readily found in the plaques. However, recent studies have shown that the nonaggregated, soluble assemblies of Aβ have the potential to stimulate neuronal dysfunction and may play a prominent role in the pathogenesis of Alzheimer's disease.</p> <p>Methods</p> <p>Soluble, synthetic Aβ1–42 oligomers were prepared producing mainly dimer-trimer conformations as assessed by SDS-PAGE. Similar analysis demonstrated fibril preparations to produce large insoluble aggregates unable to migrate out of the stacking portion of the gels. These peptide preparations were used to stimulate primary murine microglia and cortical neuron cultures. Microglia were analyzed for changes in signaling response and secretory phenotype via Western analysis and ELISA. Viability was examined by quantifying lactate dehydrogenase release from the cultures.</p> <p>Results</p> <p>Aβ oligomers and fibrils were used to stimulate microglia for comparison. Both the oligomers and fibrils stimulated proinflammatory activation of primary microglia but the specific conformation of the peptide determined the activation profile. Oligomers stimulated increased levels of active, phosphorylated Lyn and Syk kinase as well as p38 MAP kinase compared to fibrils. Moreover, oligomers stimulated a differential secretory profile for interleukin 6, monocyte chemoattractant protein-1 and keratinocyte chemoattractant when compared to fibrils. Finally, soluble oligomers stimulated death of cultured cortical neurons that was exacerbated by the presence of microglia.</p> <p>Conclusion</p> <p>These data suggest that fibrils and oligomers stimulate unique signaling responses in microglia leading to discrete secretory changes and effects on neuron survival. This suggests that inflammation changes during disease may be the consequence of unique peptide-stimulated events and each conformation may represent an individual anti-inflammatory therapeutic target.</p
Nebular spectroscopy of SN 2014J: Detection of stable nickel in near infrared spectra
We present near infrared (NIR) spectroscopy of the nearby supernova 2014J
obtained 450 d after explosion. We detect the [Ni II] 1.939 m line
in the spectra indicating the presence of stable Ni in the ejecta. The
stable nickel is not centrally concentrated but rather distributed as the iron.
The spectra are dominated by forbidden [Fe II] and [Co II] lines. We use lines,
in the NIR spectra, arising from the same upper energy levels to place
constraints on the extinction from host galaxy dust. We find that that our data
are in agreement with the high and low found in earlier studies
from data near maximum light. Using a Ni mass prior from near maximum
light -ray observations, we find 0.05 M of stable nickel
to be present in the ejecta. We find that the iron group features are
redshifted from the host galaxy rest frame by 600 km s.Comment: 6 pages, 4 figures, submitted to A&
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